Help on 360 build

I'd pull one of the valve springs and take it to a shop and have them measure the spring pressure at closed and open around .500 " lift, see what the numbers come back as and go from there. Or look up the specs for the recommended spring with the 268 cam. You need to know what you have before starting any changes.

I'd be willing to bet these are single springs with a damper right ? Most all of these springs are good to no more than .500" lift. I dont know what the lift range is on the extreme cams, take a look at the spring specs used for their cam applications and compare what you have - I'll bet you are fine.